Braided River Field Guide Braided River Field Guide Compiled by Barry Hibbert and Kerry Brown Plant illustrations from Wild Plants of Mount Cook National Park by Hugh Wilson Some illustrations were based on original drawings in: Freshwater Life by Michael Winterbourn & Karen Mason – common freshwater snail, all insects on pages 18–21, water spider Butterflies of New Zealand by W.B.R. Laidlaw – boulder copper butterfly The Grasshoppers of New Zealand by R.S. Bigelow – minute grasshopper Common Insects 2 by Annette Walker & Geoffrey Cox – tiger beetles, chafer beetle The Field Guide to the Birds of New Zealand, Barrie Heather, Hugh Robertson & Derek Onley – all birds Cover photo: Ahuriri River, Mackenzie Basin Produced by Project River Recovery, Department of Conservation, Twizel and Meridian Energy Limited Copyright 2001, Department of Conservation ISBN 0-478-22121-5 Contents Introduction 4 Plants 5 Invertebrates 17 Lizards 26 Fish 28 Frog 33 Birds 33 Mammals 45 Threats to braided rivers 48 Glossary and further reading 51 Introduction Braided rivers are very special habitats with plant and animal communities that are found nowhere else in the world. Physically similar extensive braided rivers are rare world-wide and occur only in Alaska, Canada and the Himalayas. Canterbury contains 60% of the braided- river habitat in New Zealand, and the Mackenzie Basin contains some of the most pristine of these rivers. This field guide briefly describes the ecology of some eighty introduced and native species found in the braided rivers and wetlands of the Mackenzie Basin, but many of these species are also found in other braided rivers. Project River Recovery (PRR) is a DOC programme that aims to maintain and enhance braided-river and wetland habitats and ecological communities in the upper Waitaki Basin. PRR is funded by Meridian Energy Limited under a compensatory agreement that recognises the adverse effects of hydro-electric power development on rivers and wetlands. DOC and Meridian Energy are working together on jointly agreed projects to protect braided river habitats and their special communities of native plants and animals. We hope that this guide adds to your enjoyment of braided rivers and wetlands by enabling you to understand more about the variety of animals and plants that live in these special ecological systems. Ahuriri River 4 Creeping pōhuehue Muehlenbeckia axillaris Status: Common native, found in both main islands, as well as Australia. Description: Wiry-stemmed shrub that grows flat on the ground. Dark green leaves; small yellowish-white flowers (December–March); black nut (January–April). Habitat: Scrubland riverflats, from coast to mountain slopes. Cushion forget-me-not Myosotis uniflora Status: Uncommon endemic, found only in the upper reaches of some large Canterbury rivers. Description: Forms small rounded cushions. Closely packed hairy leaves; small sulphur- yellow flowers (November); tiny fruit (December–January). Habitat: Grows exclusively on high-country shingle riverbeds. 5 Mat daisy Raoulia hookeri Status: Locally common endemic, found in three main islands. Description: Mat-like plant that forms large patches on ground. Small boat-shaped, greyish white leaves; button-shaped yellow flower heads (January–February); fluffy seeds. Habitat: Glacial moraines and mountain riverflats, also extends into neighbouring grasslands. Mat daisy/tutahuna Raoulia tenuicaulis Status: Locally common endemic, found in three main islands. Many members of its botanical group are popularly called ‘vegetable sheep’. Description: Moss-like mat-forming plant that can spread up to 1 metre in diameter. Small, overlapping, pale green leaves; funnel-shaped yellow-tipped flower heads (November); fluffy seeds. Habitat: Glacial moraines and mountain riverflats. 6 Scleranthus uniflorus Status: Locally common endemic, found in three main islands (most widespread in South Island). Description: Dense cushion-forming plant that resembles moss. Very small, closely packed orange-green leaves; tiny flowers and fruit (November–January). Habitat: Inland riverbeds and high-country tussock land. Dwarf heath Pentachondra pumila Status: Locally common native, found in all three main islands, as well as Australia. Description: Small dense shrub that can form extensive, ground-hugging patches. Dark purplish-green leaves; small star-shaped white flowers (November–February); red fruit. Habitat: Mountain slopes and subalpine shrublands. 7 Native daphne/pinātoro Pimelea prostrata Status: Widespread and locally common endemic found in both main islands. Description: Low growing hebe-like shrub, with interlacing branches. Small green leaves edged with red; strongly scented white flowers (November); white fruit (December– February). Habitat: Dry places, from rocky beaches to mountain riverflats. Porcupine shrub Melicytus alpinus Status: Common endemic, found in South and Stewart Islands. Description: Extremely tough low shrub with stout branches and spine-like branchlets. Small dark green leaves; bell-shaped pale yellow flowers (November–December); white fruit (December–April). In more exposed places, leaves are sparsely placed on plant. Habitat: Open high country in dry rocky places. 8 Willowherb Epilobium microphyllum Status: Locally common endemic, found in both main islands. Description: Small clump-forming herb with wiry stems. Green or red-brown leaves; white flowers (December–February); striped black and white seed capsules. Habitat: High-country shingle riverflats. Epilobiums are usually the first plants to colonise dry, stable riverbeds. Willowherb Epilobium rostratum Status: Locally common endemic, found only in the South Island. Description: Small, partly sprawling herb. Dull green leaves; white or pink flowers (January); seed capsules have beaked tip. Habitat: Inland shingle riverbeds. 9 Helichrysum depressum Status: Common endemic. Apart from one small population in Hawke’s Bay, this plant is known only from the South Island. Description: Low, dead-looking shrub. Scaly, grey leaves; small yellowish flowers (January–February); fluffy windborne seeds. Habitat: Gravelly riverbeds and glacial moraines. Matagouri/tūmatakuru Discaria toumatou Status: Common and widespread endemic, found in both main islands. Known as ‘Wild Irishman’ by early European settlers. Description: Spiny shrub or small tree that can grow up to 6 metres. Small dark green leaves; scented white flowers (November– December); fruit is a small dry capsule (January–March). Habitat: Most common in dry inland valleys and riverbeds east of the Southern Alps. (Because it fixes nitrogen from the air, matagouri is an important pioneer plant on bare sites with newly developing soils.) 10 Grey woollyhead Craspedia lanata Status: Locally common endemic, found only in the South Island. Description: Small herb. Woolly stems and greyish white leaves; yellow flowers (December–February); tiny fluffy seeds are dispersed in wind. Habitat: Subalpine valleys and stony riverflats. Poa maniototo Status: Common, but easily overlooked, native grass named after the Maniototo Plains. Found only in Otago and Canterbury. Description: Very small bluish-green tufts of leaves, bearing an oblong cluster of closely packed flowers (spikelets) usually seen in February. Habitat: Stony river flats of Otago and Canterbury. 11 Stonecrop/wall pepper Sedum acre Status: Locally common exotic introduced from Europe as garden plant. Its peppery- tasting leaves are poisonous. Spreading in the braided rivers of Canterbury. Description: Low-growing succulent that forms clumps or mats. Small fleshy light green leaves; yellow flowers, often abundant (January). Habitat: Grows on dry banks, stone walls and gravelly riverbeds. King devil hawkweed Hieracium praealtum Status: Abundant exotic herb, introduced from Europe. Can be a significant problem plant in open areas and grasslands. Description: Small herb with pale green leaves and long sparse hairs. Often forms extensive colonies of tufted upright leaves. Bright yellow flower heads, forming fluffy wind-dispersed seeds (November – March). Habitat: Stony ground and grassland, from lowland to alpine areas. 12 Russell lupin Lupinus polyphyllus Status: Exotic garden plant that has been spread by people into the wild in many parts of the South Island. Problem plant in the braided rivers of the Mackenzie Basin. Description: Perennial plant (dies down in winter). Downy green leaves; white, blue, pink, mauve, orange or yellow flowers carried on tall spikes (November–February); seeds are held in furry pods which explode when ripe. Habitat: Stony ground; riverflats and terraces. Yellow tree lupin Lupinus arboreus Status: Common exotic. Problem plant in Canterbury riverbeds. DOC is attempting to eradicate yellow tree lupin in the Mackenzie Basin. Description: Large shrub. Downy green leaves; sweetly scented yellow flowers (October–May); ripe seed pods explode in sun. Habitat: Most common in sandy coastal areas; also vigorously colonises inland riverbeds and terraces. 13 Crack willow Salix fragilis Status: Widespread exotic, introduced from Europe to control rivers. Now naturalised in many places. Spreads quickly in active riverbeds. Problem plant in riverbeds and wetlands. Description: Large deciduous tree with rough bark and shiny orange-brown twigs. Bright green leaves; yellowish flowers (catkins) (November). Habitat: Riverbanks and terraces; boggy ground. Viper’s bugloss Echium vulgare Status: Locally common exotic, introduced from Europe as garden plant. It was once prescribed as a remedy